we are implementing Tableau server and integrating authentication with Active Directory.

Our Target is to map all members of a certain active directory group to a single Tableau user so that we can eliminate accounts sharing and each member can login using his own LDAP credentials

example :

LDA Group called developers has 5 members , we need to map the 5 members to a single Tableau user (called Developers team) so that each developer can login using his own LDAP credentials and still have access .

I don't quite understand your question. Nonetheless, when you sync Tableau Server groups to the integrated Active Directory group, then each user of the developer team will be able to login to Tableau Server with their own credentials. And then, in terms of permissions, you should assign via the group to either the projects or workbooks. See best practices here Structure Content Projects, Groups, and Permissions and let me know if this helps:

what we want to accomplish is to map all members of the LDAP group to a single Tableau server user so that each team can use only one tableau user instead of separate tableau user for every team member

I see. It's highly not really advised to share a common userid as you lose all auditability on who did what, and when a user logs in, there's a session that gets created and there's potential for things to go wrong in terms. What I would advise instead is to sync AD to the Tableau group and assign permissions via this group. And if you're insistent on a common userid, then I guess you can setup a generic service account that everybody shares, but not advisable / not endorsed.

Another question, If we create a group in LDAP Server, we called TableauGroup, and when Tableau server integrate with LDAP Server, only synchronize the users in TableauGroup, in this way, no need to create or manage the users in tableau.

I am not sure whether this way can work, if you have some experience of it , please give me some reference, thank you.